Kaoutzanis M C, Peterson J W, Anderson R R, McAuliffe D J, Sibilia R F, Zervas N T
Neurosurgical Service, Massachusetts General Hospital, Boston.
J Neurosurg. 1995 Feb;82(2):256-61. doi: 10.3171/jns.1995.82.2.0256.
Vasodilation of rabbit carotid arteries induced by a pulsed-eye laser was studied in vitro to clarify the underlying mechanism. Artery segments were double cannulated in a pressure-perfusion apparatus which, under physiological conditions, allows for differential application of various solutions, pharmacological agents, and pulsed-dye laser light. Vasoconstriction was activated using both pharmacological and nonpharmacological agonists. Laser energy at a wavelength of either 480 or 575 nm was applied intraluminally in 1-microseconds pulses, which caused dilation of the arteries if hemoglobin was present in the lumen at sufficient concentration. Induced vasodilation did not specifically require the presence of hemoglobin; the same phenomenon could be repeated using an inert dye such as Evans blue as an optical absorber of laser energy. The optical density of the absorber, the number of applied laser pulses, and total amount of applied energy directly influenced the vasodilatory response. Laser-induced vasodilation was possible in both normal vessels and vessels denuded of endothelium. Pulsed-dye laser-induced vasodilation is therefore not a phenomenon mediated through chemical processes, but is rather a purely physical process initiated by the optical absorption of laser energy by the intraluminal medium, which probably induces cavitation bubble formation and collapse, resulting in the vasodilatory response of the vessel.
为阐明其潜在机制，对脉冲式眼科激光诱导的兔颈动脉血管舒张进行了体外研究。动脉段在压力灌注装置中进行双插管，在生理条件下，该装置可对各种溶液、药物制剂和脉冲染料激光进行不同的应用。使用药理学和非药理学激动剂激活血管收缩。腔内施加波长为480或575 nm的激光能量，以1微秒的脉冲形式，如果腔内血红蛋白浓度足够，则会引起动脉扩张。诱导的血管舒张并不特别需要血红蛋白的存在；使用惰性染料如伊文思蓝作为激光能量的光学吸收剂也可重复相同现象。吸收剂的光密度、施加的激光脉冲数量和施加的总能量直接影响血管舒张反应。正常血管和内皮剥脱的血管都可能发生激光诱导的血管舒张。因此，脉冲染料激光诱导的血管舒张不是通过化学过程介导的现象，而是由腔内介质对激光能量的光学吸收引发的纯粹物理过程，这可能会诱导空化泡的形成和塌陷，从而导致血管的舒张反应。
